1. Field
The present disclosure relates to a power circuit and a Direct Current (DC) to DC converter thereof, and more particularly to a power circuit and a DC to DC converter thereof with a low circulation loss.
2. Related Art
A diode is quite widely applied to an electronic product. Usually, a rectifying function of the diode is used. That is to say, a rectifying effect is achieved with a characteristic that the diode is in a conducted state when in a forward bias condition and is in a cut-off state and not conducted when in a reverse bias condition.
When the diode is in the conducted state, all currents flow through the diode. At this time, energy consumed by the diode is a product obtained by multiplying a cut-off voltage of the diode by the current. That is to say, the larger the cut-off voltage of the diode or the current is, the larger the consumed energy (usually referred to as a circulation loss) will be. Therefore, in order to reduce the circulation loss of the diode, the current flowing through the diode and the cut-off voltage of the diode may be reduced. When the diode is used as a rectifier element, the current flowing through the diode usually is a main current, which has little chance to be reduced. The cut-off voltage of the diode is related to a structure and a material of the diode, for example, a forward bias (cut-off voltage) of a diode with silicon as the main material is approximately 0.7 volts (V), a cut-off voltage of a silicon carbide diode applicable to a high voltage is approximately from 1.0 V to 1.2 V, and a forward bias of a germanium diode is approximately 0.2 V.
In addition, when being used, the diode also generates a switching loss in addition to the circulation loss, in which the switching loss refers to a loss that occurs at the moment when the diode is switched to be conducted or cut-off. When the rectifier diode is applied to a current supplier, a bridge rectifier, a flyback DC to DC converter, or a forward DC to DC converter, the circulation loss and the switching loss usually occupy almost a half of the total energy loss of a power source supplier. Therefore, under the energy-saving trend, how to reduce the energy loss of the rectifier diode remains a subject continuously concerned by the industry.